The subject disclosure relates to the printing arts, the copying/scanning arts, the image processing arts, the color processing arts, and the like.
While historically images were captured using photographic film, modern digital devices (such as scanners, cameras, etc.) capture images as pixels electronically, and most such digital devices capture images in a color space referred to as RGB, or red-green-blue color space. The RGB color space is utilized by image capture devices because such devices commonly include sensors that distinguish between the red, green, and blue colors.
When processing images captured by digital devices to make color corrections, remove undesirable artifacts, improve image resolution, suppress background, prepare images for printing or display, etc. (which is sometimes referred to as image path processing) it is often useful to first convert the electronic images into a color space that is device independent, such as the CIEL*a*b* color space.
The L*a*b* color space has an L dimension for lightness and a* and b* that are color-component dimensions (green-red and blue-yellow, respectively). The L*a*b* color space includes all perceivable colors, which means that its gamut exceeds those of the RGB and CMYK color spaces. The L*a*b* color space is device independent, which means that the colors are defined independent of their nature of creation or the device they are displayed on.
Multifunction devices, including printing devices, generally operate in a smaller gamut color space, such as the RGB or CMYK color spaces, that are named based on the colors of the marking materials (e.g. inks, toners, etc.) used; such as red, green, and blue (RGB); or cyan, magenta, yellow, and black (CMYK). Thus, in order to print images represented in the L*a*b* color space, the image data must be transformed to either the RGB or CMYK color space.
Auto-color copying and scanning is an important feature of multifunction devices. Auto-color is a mode that generates a color or monochrome output based on an input document without user selection or effort. A document is imaged usually by a scanning device in an RGB color space and printed by a printer, usually in a CMYK color space. Traditionally, in hardware-based image path, neutral page detection is performed on the entire input page and the result is used to control down-stream processing. In some systems for auto-color copy modes, both a device dependent color space (CMYK) and a monochrome rendered binary image are generated while the neutral page detection process is in progress. One of the binary images, either the CMYK or monochrome image, is eventually selected as the output based on the final neutral page detection result.
Software based image path has recently experienced wider adoption due to its advantage in cost and flexibility over hardware-based image path. However, one key challenge in implementing a software-based image path is performance optimization. It is desirable to identify and make use of every opportunity to reduce the processing time to enhance system performance. Currently, in a software-based image path, the auto-color feature is implemented the same way as in the hardware-based image path, which is not as efficient as possible. That is, in hardware image paths, CMYK and monochrome images are simultaneously generated while the neutral page detection is in progress. In a software-based image path, it is desirable to reduce the amount of processing and time in order to improve the overall system performance, e.g., the amount of computations may be reduced by terminating monochrome renderings when color is detected.
Accordingly, a method and system to improve the auto-color feature of multifunction devices utilizing software-based image path with increased efficiency, faster processing, and improved quality is needed.